Urinary Oestrogens in Ovariectomized Cows after Administration of ACTH

Two ovariectomized cows were injected intramuscularly once daily with 300 i.u. of ACTH*) on three consecutive days. The urine was collected with the aid of rubber mats. The method for oestrogen analysis comprised acid hydrolysis of the urine, saponification of the phenolic fraction, inethylation and column chromatography followed by fluorimetry (Lunaas 1964 and unpublished).     

Amniotic and Allantoic Fluid Levels of Oestrogens at Different Stages of Development in the Goat

During our studies on certain aspects of reproduction in the goat (Lyngset 1971) we collected several samples of foetal fluid which were stored in the frozen state for further investigation. We have now processed this material with respect to contents of oestrogens.     

Bovine Colostrum Levels of Oestrone and Oestradiols

The levels of free and conjugated oestrone, oestradiol-17β and oestradiol-17α were estimated in bovine colostrum of the 1st, 2nd and 3rd drawing. The values obtained of free oestrone and oestradiol-17β were generally below the lowest value significantly (P = 0.01) different from zero (4.5–5.0 µg per 1) in the method applied. The values of conjugated oestrone and oestradiol-17β in the first drawing exceeded the lowest value significantly different from zero (1.5–2.0 µg per 1) by factors of 2–4 and averaged 6.1 and 3.7 µg per 1 respectively in the five cows examined. The levels of conjugated oestrone and oestradiol-17β in the 2nd and the 3rd drawing were apparently lower than in the 1st drawing. As compared with the values obtained of free and conjugated oestrone and oestradiol-17β, the corresponding values of oestradiol-17α were generally much smaller, in none of the samples exceeding 1 µg per 1. In some samples oestradiol-17α could not be detected. The results are discussed in relation to previous bioassays of colostrum oestrogens.     

Distribution of Oestrone and Oestradiol in the Bovine Ovary

The levels of oestrone (oe1) and oestradiol (oe2) were estimated with chemical methods in single bovine ovaries of various categories, including ovaries from different phases of the oestrous cycle and from early pregnancy and in cystic ovaries. In the luteal tissue the levels of the two oestrogens were generally found to be very low. In the follicular apparatus (including follicular fluid and residual tissue) the oestrogen contents varied considerably and were higher in the preovulatory ovaries (means: 165 ng. oe1 868 ng. oe2) than in ovaries representing other phases of the oestrous cycle (means during the estimated week 1, 2 and 3 after ovulation respectively: 28 — 18 — 30 ng., oe1 and 91 — 63 — 96 ng. oe2) and from early pregnancy (means: 25 ng. oe1, 42 ng. oe2, foetal length: 2–12 cm.). In the cystic ovaries the contents of oestrogens were higher (means: 230 ng. oe1, 1140 ng. oe2) than in the preovulatory ovaries but the concentrations were lower (means: 45 ng. oe2 per g. as compared to 142 ng. oe2 per g.). The means of the ratios between oestradiol and oestrone in preovulatory and in cystic ovaries were almost identical (mean percentages oe2 of the sum total oe1 and oe2: 83.3 as compared to 82.5). The contents of oestrogens (as oe1 + oe2) of the fluid in follicles or cysts were highly correlated with the contents of oestrogens in the corresponding residual tissue (r = 0.90) and on the average about four times as large. The percentages oestradiol of the sum total oestrone and oestradiol in the fluid and in the corresponding residual tissue were also correlated (r = 0.79). The concentration of oestradiol (and oestrone) in the fluid of follicles and cysts was extremely variable (0.7–600 ng. per ml.) and was apparently not related to the size of the structures except that the concentration in the fluid of preovulatory follicles tended to be higher than in the fluid of small follicles (containing less than 1.5 ml. fluid) and of large follicles or cysts (2–30 ml. fluid).     

The Exchange of Radioactive Magnesium in the Tissues of the Cow,Calf and Fetus

Calves and pregnant cows were injected with tracer doses of radioactive magnesium and killed at intervals. The pattern of exchange of the isotope with intracellular magnesium in various tissues was broadly similar to that reported for other species except that the equilibration rate was much slower than in the rat. An exception was that the testis magnesium in the 6 week old calves used exchanged more rapidly than in 150 g rats. The exchange of isotope from maternal plasma to fetal tissues was extremely slow.     

Urinary Oestrogen Excretion in the Goat During the Oestrous Cycle and after Administration of Pregnant Mare Serum Gonadotrophin (PMSG)

Two goats were placed in cages constructed for urine collection. Samples were taken daily and stored in the frozen state until analysis. The urine was processed according to a method designed for determination of oestrone and oestradiol-17 α in bovine urine (Lunaas unpublished).