No abstract

Foetal human pituitaries of 8\p=n-\18weeks gestational age were maintained in tissue culture for up to 6 days. No morphological change was observed in the tissue during this period. Radioactive glucosamine was continuously incorporated into medium protein and the levels of luteinizing hormone (LH), follicle-stimulating hormone (FSH) and growth hormone in the medium increased with the duration of the culture. Theophylline stimulated the release of both LH and FSH consistently over the 6 days, and the total amount of each hormone released over this period was significantly greater than that in unstimulated control cultures. Cyclic adenosine 3' , 5' \ x=req-\ monophosphate stimulated FSH release to some extent but had no significant effect on LH release.

Recent reports have recorded changes in the concentrations of oestradiol-17\g=b\, progesterone and luteinizing hormone (LH) in the plasma of the Beagle bitch during the oestrous cycle and pregnancy (

A double antibody radioimmunoassay for canine luteinizing hormone (LH) was devised. The assay can measure immunoreactive LH in the peripheral plasma of the normal male and female dog. An increase in hormone concentration was found on the 2nd day of oestrus in the female. Ovariectomy raised plasma concentrations of the hormone to levels greater than those observed during oestrus. The administration of LH-releasing factor induced a rapid increase in the plasma concentrations of LH.

Oestradiol-17\g=b\,diethylstilboestrol (DES), dl-dihydrodibutylstilboestrol (dl-DHBS) and meso-dihydrodibutylstilboestrol (meso-DHBS) were injected intramuscularly into male Sprague-Dawley rats in a daily dose of 100 \ g=m\ g for a period of 10 days. Oestradiol-17\g=b\ and DES decreased the weight of the prostate and seminal vesicles to the same extent, whereas meso\x=req-\ DHBS was less effective. dl-DHBS was almost inactive. Only oestradiol\x=req-\ 17\g=b\ and DES caused a decrease in the weight of the testes. The adrenal glands increased in weight after administration of either oestradiol-17\g=b\, DES or meso-DHBS.Four hormones in the plasma were measured: testosterone, androstenedi\x=req-\ one, prolactin and interstitial cell-stimulating hormone (ICSH). DES decreased the plasma concentration of both ICSH and testosterone. Oestradiol-17\g=b\ and meso-DHBS administration resulted in a lowering of the plasma testosterone concentration with no effect on ICSH. Oestradiol-17\g=b\, DES and meso-DHBS markedly increased plasma prolactin concentrations. dl-DHBS appeared to have little biological effect causing only very small changes in all the parameters investigated.