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SUMMARY
Plasma cortisol concentrations increased after injections of nicotine. This increase was variable and was no greater than that seen after substitution of normal saline for nicotine. Plasma cortisol concentrations did not increase after nicotine in patients with hypopituitarism and after inhibition of corticotrophin release with triamcinolone. It is concluded that the increased plasma cortisol concentration after injection of nicotine was due to non-specific pituitary stimulation associated with the experimental procedure and not due to any direct effect of the nicotine. Nicotine resulted in a similar increase in plasma cortisol in four patients with diabetes insipidus. Neither rapid infusion of hypertonic mannitol nor ingestion of ethanol had a consistent effect on the plasma cortisol concentration. It is therefore concluded that the antidiuretic hormone is not the 'corticotrophin release factor' in man.
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ABSTRACT
Using an exchange assay to measure occupied and unoccupied binding sites, the glucocorticoid receptor in rat skin cytosol has been measured after adrenalectomy and parenteral steroid administration. Adrenalectomy increased the number of receptor sites with maximal effect after 5 days, after which numbers decreased to those of intact animals. Injection of adrenalectomized animals with the unlabelled agonist corticosterone resulted in a rapid dose-related decrease in the number of cytosolic receptor sites at 30 min whereas the antagonist progesterone had no effect. It is concluded that changes in glucocorticoid concentration lead to rapid inverse changes in cytosolic receptor.
J. Endocr. (1984) 102, 161–165
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The anterior pituitary has an important role in the control of sebaceous gland activity. This effect is mediated in part by thyrotrophic hormone (TSH) and adrenocorticotrophic hormone (ACTH) through their actions on the thyroid and adrenal glands respectively (Thody & Shuster, 1970a, 1971, 1972a). Ablation and replacement experiments suggest that the gonads also have a major influence (Thody & Shuster, 1970a, b), but although there is evidence that gonadotrophins will stimulate sebaceous glands in the human male (Strauss & Pochi, 1963) no data are available from experimental animals. We therefore decided to examine the effect of gonadotrophins on sebum secretion in the rat.
Male Wistar rats were hypophysectomized when 8–9 weeks old and 4 weeks later received either 0·9 units human menopausal gonadotrophin (Humegon)/day or no treatment. Humegon was dissolved in 0·9% NaCl solution and subcutaneous injections were given daily for a period of 2 weeks. At
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Removal of the pituitary gland from the rat produces a decrease in the rate of sebum secretion (Nikkari & Valavaara, 1969; Ebling, Ebling & Skinner, 1969; Thody & Shuster, 1970 a). However, it is not established which pituitary hormones are involved in the control of sebaceous gland activity. In this study we have examined the effect of a new pituitary hormone, β-lipotrophin (β-LPH) (Birk, & Li, 1964; Li, 1968), on the rate of sebum secretion in the rat.
Female Wistar rats were ovariectomized when 5–6 weeks old and hypophysectomized at 7–8 weeks of age. Two weeks later the rats were divided into two groups and received either no hormone treatment (controls) or 0·1 mg β-LPH/day. The injections were given subcutaneously and continued for 2 weeks. At the end of this time the rate of sebum secretion was measured by the method of Archibald & Shuster (1970).
In this method the
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SUMMARY
The effect of α-MSH on sebum secretion and preputial gland weight was examined in intact, castrated and hypophysectomized male rats and in hypophysectomized rats receiving treatment with either testosterone propionate (TP) or progesterone. After treatment with α-MSHMSH for 2 weeks, increases in sebum secretion occurred in intact, castrated and hypophysectomized rats, but larger responses were found in the hypophysectomized rats that had received treatment with either TP or progesterone, suggesting that α-MSH acts synergistically with TP and progesterone to stimulate sebum secretion. α-Melanocyte-stimulating hormone also increased preputial gland weight in intact rats, but there was no response after castration and only a small response after hypophysectomy. However, when the hypophysectomized rats received simultaneous treatment with either TP or progesterone, α-MSH increased preputial gland weight.
It is suggested that α-MSH acts directly on the sebaceous glands to stimulate lipogenesis and, together with steroid hormones, may have an important role in controlling sebaceous gland function in the rat and other hairy mammals. With the evolution of hair, certain of the MSH peptides may have lost their significance as pigmentary hormones and have developed a sebotrophic function. For this reason, it might be more appropriate to refer to these peptides as the 'sebotrophins'.
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SUMMARY
Thyroidectomy of intact and castrated rats produced significant reductions in their rates of sebum secretion. Replacement therapy with thyroxine (T4) increased the rate of sebum secretion of the castrated-thyroidectomized rats. Treatment with testosterone propionate also stimulated sebum secretion in castrated-thyroidectomized rats. When given together these two hormones had an additive effect on the rate of sebum secretion.
Thyrotrophic hormone (TSH) stimulated sebum secretion in castrated-hypophysectomized, but not in thyroidectomized rats.
It is concluded that TSH affects sebum secretion through its action on the thyroid, presumably by stimulation of T4 secretion.
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SUMMARY
Adult male rats which had been castrated prepuberally secreted less sebum than intact rats. When hypophysectomy followed castration there was a further decrease in sebum secretion. Treatment of the castrated and hypophysectomized castrated rats with testosterone propionate produced a large and comparable increase in the sebum secretion of both groups. Testosterone propionate also caused a marked increase in the preputial gland weight of the castrated rats, although a much smaller response occurred after hypophysectomy. The effect of hypophysectomy on the response of the sebaceous and preputial glands to testosterone is discussed.
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It is generally believed that the activity of the sebaceous glands depends to a large extent on the gonads. The pituitary also appears to be involved in the physiology of these glands (Ebling, Ebling & Skinner, 1969; Nikkari & Valavaara, 1969; Thody & Shuster, 1970). The relationship between the pituitary and the sebaceous glands may be exerted via growth hormone and prolactin for Ebling et al. (1969) have shown that these pituitary hormones facilitate the effect of testosterone on sebum secretion. This present study was carried out to see whether the pituitary influence on sebum secretion is also mediated through the thyroid and adrenal glands.
The rate of sebum secretion was measured (Archibald & Shuster, 1969) in 12- to 15-week-old rats which had received one of the following treatments: castration, castration and adrenalectomy, castration and thyroidectomy, castration and hypophysectomy, or no treatment (intact controls). Castration was carried out when the
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SUMMARY
1. Plasma cortisol concentrations, and the urinary output of free and conjugated Porter-Silber reacting steroids, 17-ketosteroids (17-KS), 'total 17-OH CS', urinary cortisone and cortisol, free and conjugated tetrahydrocortisone and cortisol were measured before and after a 1 l. water load.
2. The plasma cortisol concentration fell within 30 min of water ingestion, and tended to increase as diuresis declined.
3. There was a simultaneous increase in the urinary output of 17-KS, total 17-OH CS, and free Porter-Silber reacting steroids. In contrast, urinary excretion of glucuronide-conjugated corticosteroids did not increase during diuresis.
4. The implications of these findings are discussed and it is concluded that (a) the enhanced corticosteroid output during water diuresis is renal in origin, suggesting that tubular factors play a part in the excretion of these hormones; and (b) the role of the adrenal in the excretion of a water load is permissive.
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SUMMARY
Adrenalectomy caused a decrease in the rate of sebum secretion of male rats.
On the other hand treatment with adrenocorticotrophic hormone (ACTH) produced a large increase in the rate of sebum secretion in hypophysectomized—castrated rats and restored it to the level in castrated rats. ACTH also stimulated sebum secretion in castrated rats after removal of the adrenals, although this increase was not significant.
These findings suggest that a pituitary—adrenal—sebaceous gland system may exist. Adrenal androgens may play a significant part in this relationship.
Although ACTH probably stimulates sebum secretion through its action on the adrenals it is possible that this pituitary hormone may have some direct effect on sebaceous gland activity.
