Search Results

You are looking at 1 - 6 of 6 items for

  • Author: I Rodriguez x
  • Refine by Access: All content x
Clear All Modify Search
Restricted access


Two hypophysial partes distales were grafted under the kidney capsule of intact female rats. The plasma prolactin levels 15, 45 and 90 days after the operation were determined. At the same postoperative intervals the grafted glands of some of the operated rats were processed for conventional light and electron microscopy and for the demonstration of prolactin, FSH and LH according to the unlabelled immunoperoxidase procedure. The ultrastructural characteristics of the transplanted secretory cells and the amount and distribution of the immunoreactive material within their cytoplasm were used to evaluate approximately the secretory activity of these cells.

Although levels of prolactin in the three experimental groups were significantly higher than those in control rats, a decrease in prolactin level was detected in 71% of the samples taken 45 days after operation. At day 15 the graft was completely surrounded by lymphoid cells whereas at day 45 these cells had invaded the whole graft. In the group sampled at day 90 the graft was free of lymphoid cells. When traced immunocytochemically the three types of cells followed different patterns of evolution after transplantation. Most prolactotrophs were hypertrophied in all groups but, in addition, they underwent a process leading to hyperplasia some time between days 45 and 90 after operation. Syncytial formations which probably correspond to multinucleated prolactotrophs were present only in the group sampled at day 90. The number of LH and FSH cells had decreased in the group at day 45 and by day 90 the former remained scarce but immunoreactive FSH cells were no longer found. At the ultrastructural level clear signs of involution of gonadotrophs and degradation by macrophages were seen in the graft 45 days after operation.

The relation between the morphology and hormone content of the graft and hormone content of the plasma is discussed, together with several questions raised by the results. Pituitary transplantation can be used as an experimental model only if the time-dependent changes described here are taken into account.

Restricted access


Laboratorio de Investigaciones Endócrino-Oncológicas, Instituto de Histología y Embriología, Facultad de Ciencias Médicas, U.N.C., 5.500 Mendoza, Argentina

(Received 16 August 1976)

The secretion of prolactin by the pars distalis transplanted at a site remote from the hypothalamus was first reported by Desclin (1950). This author observed the persistence of the ovarian corpora lutea in hypophysectomized, oestrogen-treated rats bearing a pars distalis graft under the kidney capsule. Everett (1954, 1956) confirmed Desclin's findings, but in addition demonstrated that liberation of prolactin from the pituitary gland graft occurred independently of oestrogen. Mühlbock & Boot (1959) found that transplanted hypophyses release prolactin continuously. Chen, Amenomori, Lu, Voogt & Meites (1970) have determined the serum prolactin concentrations, measured by radioimmunoassay, in hypophysectomized, ovariectomized rats with 1, 2 or 4 pars distalis grafts under the kidney capsule. Under these conditions the amount of prolactin released by the transplants was judged to be similar to that

Restricted access

A C Garcia-Montero, I De Dios, A I Rodriguez, A Orfao, and M A Manso


The effect of glucocorticoid deprivation induced in male rats by adrenalectomy on the pancreatic zymogen granules was studied. Zymogen granules were purified from control, sham-operated and adrenalectomized animals studied 1, 3 and 7 days after surgery. The zymogen granules were characterized by flow cytometry, and in each granule the size (based on the forward or low angle light scatter (FSC) parameter), membrane complexity (based on side or 90° light scatter (SSC) parameter) and amylase content were evaluated. Amylase content/DNA ratio in pancreatic homogenates was also analyzed. The zymogen granules of the control rats were found to be distributed in two populations: a major one – R1 (95·45 ± 1·21%) – containing zymogen granules with a smaller mean size and complexity, and a minor population - R2 (4·45 ± 0·24%) – the granules of which had a mean size which was larger and more complex. At day +1 after adrenalectomy the zymogen granules were significantly (P<0·05) smaller than those of control animals. The R2 zymogen granules were similar to those from R1 as regards their size, but were more complex, suggesting that the immediate effect of glucocorticoid deprivation is to induce a depletion of the larger granules presumably belonging to the R2 population. The amount of amylase per granule did not vary at day +1 after adrenalectomy, although the amylase content/size ratio per granule was significantly (P<0·001) increased. This mechanism could be explained in terms of the existence of a bypass defined in the adrenalectomized animals between the granular content and cytosolic enzymes. Prolongation of the adrenalectomy period to 3 and 7 days resulted in a progressive increase in zymogen granule size and complexity, both parameters showing similar characteristics to those of the controls at day +7 after adrenalectomy. However, the percentage of zymogen granules within the R1 and R2 populations was clearly different from that of controls since the R2 population was much more numerous (11·25 ± 0·75% and 15·25 ± 1·15% (adrenalectomized rats at days +3 and +7 respectively) versus 4·45 ± 0·24% (controls)). An increase in the content of amylase per DNA was observed in adrenalectomized rats at day +1 although this transient effect cannot be related to glucocorticoid deprivation because it was also observed in sham-operated rats (day +1). However, a significant reduction, nearly 64%, in the amylase content/DNA ratio is produced by the absence of glucocorticoids 7 days after adrenalectomy and this is associated with a reduction in the content of amylase in each individual zymogen granule which reaches a minimum 3 days after adrenalectomy. It should be noted that, despite this, the enzyme concentration in each granule remains constant as there is a parallel decrease in the zymogen granule amylase content and size.

Journal of Endocrinology (1995) 147, 431–440

Free access

I Rodriguez, E Fluiters, LF Perez-Mendez, R Luna, C Paramo, and RV Garcia-Mayor

This study was carried out to investigate the clinical and biochemical factors which might be of importance in predicting the outcome of patients with myxoedema coma. Eleven patients (ten female) aged 68.1+/-19.5 years attended our institution over a period of 18 years.Glasgow and APACHE II scores and serum free thyroxine and TSH were measured in all the patients on entry. Patients were selected at random to be treated with two different regimens of l-thyroxine.Four patients died with the mortality rate being 36.4%. The patients in coma at entry had significantly higher mortality rates than those with minor degrees of consciousness (75% vs 14.3% respectively, P=0.04). The surviving patients had significantly higher Glasgow scores than those who died (11.85+/-2.3 vs 5.25+/-2.2 respectively, P<0.001). Comparison of the mean values of APACHE II scores between the surviving group and those who died was significantly different (18.0+/-2.08 vs 31.5+/-2.08 respectively, P<0.0001).The degree of consciousness, the Glasgow score and the severity of the illness measured by APACHE II score on entry were the main factors that determined the post-treatment outcome of patients with myxoedema coma.

Free access

S Bas, E Aguilera-Tejero, A Bas, J C Estepa, I Lopez, J A Madueño, and M Rodriguez

The influence of secondary hyperparathyroidism (2 HPT) on the set point of the parathyroid hormone (PTH)-Ca2+ curve is controversial. In vitro experiments have shown an increase in the set point. However, clinical studies with hemodialysis patients have provided a variety of results (increases, decreases and no changes in the set point have been reported). The present study was designed to investigate the influence of the progression of 2 HPT on the set point of the PTH-Ca2+ curve. The PTH-Ca2+ curve and the expression of parathyroid calcium receptor (CaR mRNA) and vitamin D receptor (VDR mRNA) have been studied in normal rabbits (group I, n=9) and in nephrectomized rabbits (group II, n=18) at two stages after inducing 2 HPT: 2–3 weeks (group IIA) and 5–6 weeks (group IIB). In group I, the set point of the PTH-Ca2+ curve was 1.63±0.03 mM. A progressive hypocalcemia was detected during the evolution of 2 HPT (groups IIA and IIB). Rabbits from group IIA had a significant (P<0.001) decrease in the set point to values of 1.45±0.02 mM. However, the set point increased significantly in group IIB (P<0.001) to 1.56±0.03 mM. CaR mRNA was similarly decreased in groups IIA (39±12%) and IIB (48±7%). No changes were detected in VDR mRNA. In conclusion, a reduction in the set point of the PTH-Ca2+ curve in response to decreased extracellular Ca2+ was detected in the early phases of 2 HPT. However, with the progression of 2 HPT the set point tended to increase even though extracellular Ca2+ was markedly decreased. The increase in the set point in the course of 2 HPT seems to be a complex process that cannot be fully explained by changes in parathyroid CaR mRNA or VDR mRNA.

Free access

M I Rodriguez, G Escames, L C López, J A García, F Ortiz, A López, and D Acuña-Castroviejo

Cardiac and diaphragmatic mitochondria from male SAMP8 (senescent) and SAMR1 (resistant) mice of 5 or 10 months of age were studied. Levels of lipid peroxidation (LPO), glutathione (GSH), GSH disulfide (GSSG), and GSH peroxidase and GSH reductase (GRd) activities were measured. In addition, the effect of chronic treatment with the antioxidant melatonin from 1 to 10 months of age was evaluated. Cardiac and diaphragmatic mitochondria show an age-dependent increase in LPO levels and a reduction in GSH:GSSG ratios. Chronic treatment with melatonin counteracted the age-dependent LPO increase and GSH:GSSG ratio reduction in these mitochondria. Melatonin also increased GRd activity, an effect that may account for the maintenance of the mitochondrial GSH pool. Total mitochondrial content of GSH increased after melatonin treatment. In general, the effects of age and melatonin treatment were similar in senescence-resistant mice (SAMR1) and SAMP8 cardiac and diaphragmatic mitochondria, suggesting that these mice strains display similar mitochondrial oxidative damage at the age of 10 months. The results also support the efficacy of long-term melatonin treatment in preventing the age-dependent mitochondrial oxidative stress.