These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: The effects of a single injection of progesterone on the oestrous cycle, thyroid gland activity and uterus-plasma concentration ratio for radio-iodide in the rat.
    Author: Brown-Grant K.
    Journal: J Physiol; 1967 May; 190(1):101-21. PubMed ID: 6068378.
    Abstract:
    1. A single subcutaneous injection of 5 mg, 1.25 mg or 625 mug, but not 312 mug, of progesterone in oil delayed ovulation in the rat by 1 or more days, when injected at the dioestrous stage of a 4-day oestrous cycle.2. When ovulation was delayed in this way the expected increase in the thyroid-serum concentration ratio for (131)I was also delayed but the ratio did increase when delayed ovulation occurred.3. A single injection of progesterone resulted in an increase in the uterus-plasma and oviduct-plasma concentration ratios for (131)I; the increase was greatest when steroid was injected at the dioestrous stage of the cycle and was delayed and least when the steroid was given at the pro-oestrous stage.4. Ovulation was advanced by 1 day when progesterone was injected on the second day of dioestrus in rats showing regular 5-day cycles; this ovulation was not accompanied by an increase in the thyroid-serum concentration ratio. In these experiments a dose of progesterone that failed to advance ovulation produced a rise in uterus-plasma and oviduct-plasma ratio for (131)I but no rise was seen when ovulation was induced, suggesting that oestrogen secretion had been stimulated.5. 20alpha-Dihydroprogesterone (pregn-4-en-20alpha-o1-3-one) was not effective in delaying or advancing ovulation at a dose level of 2.5 mg per rat and had no effect on the uterus-plasma concentration ratio for radio-iodide.6. These results are discussed in relation to the hypothesis that the increase in thyroid gland activity at the oestrous stage of the cycle is related to the neuro-endocrine changes that lead to ovulation.
    [Abstract] [Full Text] [Related] [New Search]