Biomedical subjects

J E Eigenmann

Publications and source records attributed to J E Eigenmann.

24 records · Page 2Linked to original sources

PubMed1981

Influence of medroxyprogesterone acetate (Provera) on plasma growth hormone levels and on carbohydrate metabolism. II. Studies in the ovariohysterectomized, oestradiol-primed bitch.

The combined effects of oestradiol and medroxyprogesterone acetate on growth hormone (GH) levels and carbohydrate metabolism were studied in 6 ovariohysterectomized dogs, which previously had shown moderate increments in GH after medroxyprogesterone acetate (MPA) administration. Oestradiol (Oe2) implants were administered 5 months after the last MPA injection, when MPA and GH levels tended to decrease. Following Oe2 administration GH levels rose significantly. Single MPA injections (100 mg) given 20 days after Oe2-priming were followed by still further increased GH levels. These GH levels were several-fold higher than GH levels achieved by previous MPA administration alone. GH levels decreased in 3 dogs after 35 days and remained elevated in the other 3 dogs as long as 70 days after MPA administration with Oe2 priming. Glucose assimilation became impaired and insulin response to a glucose load increased in relation to elevated GH levels. Oe2-primed control dogs, which received no MPA, failed to develop elevated GH levels. These findings indicate (1) that Oe2 and MPA induce overproduction in ovariohysterectomized dogs synergistically (2) that GH levels of the magnitude evoked are associated with glucose intolerance and insulin resistance.

Animals↗

PubMed1981

[Prevention of oestrus and/or pregnancy in dogs by methods other than ovariohysterectomy (author's transl)].

The present paper is based on findings reported in the literature and concerned with various possible methods of preventing heat and/or pregnancy without resorting to ovariohysterectomy. The drugs used to suppress and prevent oestrus, such as progestagens, testosterone and 19-nortestosterone derivates, are reviewed, the mechanism of action, mode of administration and advantages and disadvantages being discussed. Progestagens are particularly found to affect the uterus (CEH) and mammary glands (increased incidence of mammary tumours), and they may also induce diabetes mellitus and acromegaly. On the other hand, the untoward side-effects of 19-nortestosterone derivatives are found to be mainly due to their androgenic action, resulting in enlargement of the clitoris, vaginitis, changes of behaviour and masculinization of puppies when the drug is administered during pregnancy. Subsequently, those mechanical and surgical procedures which are less commonly employed, are discussed. The pros and cons of the various methods and drugs as well as the possible causes of the difference in gestagenic effect of a number of progestational agents are discussed in greater detail.

Animals↗

PubMed1980

Acromegaly associated with transient overproduction of growth hormone in a dog.

A 6-year-old female crossbred Belgian Shepherd Dog with features of acromegaly was monitored for almost 4 years. The history of frequent and excessive administration of a progestational agent suggested that the progestational drug induced the acromegaly. During the monitoring period. soft tissue changes diminished and there was normalization of several factors: plasma growth hormone concentration, response of plasma insulin and glucose to an oral glucose load, and response of plasma glucose hormone to the injection of insulin.

Acromegaly↗

PubMed1977

Non-suppressible insulin-like activity during acute metabolic and endocrine changes in dogs.

Non-suppressible insulin-like activity (NSILA-S) was determined in dogs after acute changes in the blood sugar and after injection of growth hormone. Serum was chromatographed over Sephadex G-50 columns equilibrated in 1 M acetic acid and NSILA-S was determined in the fractions between 55 and 85% column volume using a protein binding assay and the conventional fat pad assay. The results obtained with these two methods correlated rather well (r = 0.74). Hyperglycaemia induced by an intravenous glucose load, by intravenous administration of mannoheptulose or both was not followed by an increase in NSILA-S levels. The injection of insulin and human growth hormone did not lead to alterations of the NSILA-S levels. It is concluded that total NSILA-S levels in the dog do not change acutely following manipulations of the blood sugar and that, in all likelihood, NSILA-S plays no role in the regulation of blood glucose.

Animals↗

PubMed1977

Decrease of non-suppressible insulin-like activity after pancreatectomy and normalization by insulin therapy.

Non-suppressible insulin-like activity (NSILA-S) was determined in 5 dogs before and after pancreatectomy and again during insulin therapy. All NSILA-S determinations were carried out on serum samples which were passed over Sephadex G-50 columns equilibrated with 1 M acetic acid. The levels of NSILA-S decreased drastically shortly after pancreatectomy and rose slowly after institution of insulin therapy, to normal levels. During the period of severe diabetes after pancreatectomy the concentration of growth hormone was elevated. These findings indicate that 1) the pancreas cannot be the site of synthesis and release of NSILA-S, 2) NSILA-S levels do not always parallel growth hormone levels and 3) the synthesis and secretion of NSILA-S among other factors is under the control of insulin.

Animals↗

PubMed1977

The influence of hypophysectomy on NSILA concentrations in the dog: evidence for partially pituitary-independent regulation.

Non-suppressible insulin-like activity (NSILA) was determined in 5 dogs before and after hypophysectomy. All NSILA determinations were carried out on serum samples after acidic Sephadex G-50 chromatography by two different assay systems, i.e. a bioassay and a protein binding assay. The levels of NSILA decreased significantly after hypophysectomy and returned to near normal levels after 2 weeks. T3-, T4- and cortisol levels were drastically reduced during the entire period of the experiment. Several GH determinations after hypophysectomy revealed very low levels. Insulin-induced hypoglycaemia failed to provoke a rise of GH levels as late as 4 months after hypophysectomy. These findings indicate that: 1) The pituitary gland cannot be the site of synthesis of NSILA. 2) NSILA concentrations in the dog are maintained at a near normal level in the presence of very low growth hormone and thyroid hormone concentrations, so that these latter hormones do not appear to be the only regulatory factors concerned in NSILA synthesis.

Animals↗