In order to assess the stimulatory effect of prolactin on the secretion of progesterone from corpora lutea in lactating rats, ergocornine maleate (ECO; 1 mg/day), an inhibitor of prolactin secretion, was administered subcutaneously on days 6 and 7 of lactation in primiparous rats. By day 8 of lactation, the concentration of progesterone in ovarian venous blood fell to an undetectable level in the ECO-treated animals, while the concentration in the control animals was very high at this stage of lactation. The level of 20α-hydroxypregn-4-en3-one was significantly higher on day 8 of lactation in ECO-treated than in control rats. Lactational dioestrus was interrupted by treatment with ECO and vaginal oestrus appeared 3–4 days after the start of treatment. Administration of ECO caused deleterious depression of milk production and of food intake of mother rats. In the pair-fed control animals, lactation continued almost normally throughout the experimental period. Prolactin (1 mg/day) administered simultaneously with ECO increased progesterone to levels even higher than those in control rats and restored 20α-hydroxypregn-4-en-3-one levels to those of the controls. The effect of the drug on milk production was alleviated.
The results strongly suggest that prolactin is the most important factor in maintaining the function of corpora lutea in the lactating rat.
Journal of Endocrinology is committed to supporting researchers in demonstrating the impact of their articles published in the journal.
The two types of article metrics we measure are (i) more traditional full-text views and pdf downloads, and (ii) Altmetric data, which shows the wider impact of articles in a range of non-traditional sources, such as social media.
More information is on the Reasons to publish page.
Sept 2018 onwards | Past Year | Past 30 Days | |
---|---|---|---|
Full Text Views | 1 | 0 | 0 |
PDF Downloads | 2 | 0 | 0 |