Pituitary acidophil macroadenoma in a pygmy goat (Capra hircus hircus).

This report describes a pituitary acidophil macroadenoma in a goat. Antemortem clinical findings included hypothermia and rumen stasis. Clinicopathologic findings included refractory hypoglycemia, low total thyroxin and insulin concentrations, elevated bile acid concentration, and hyposthenuria. In addition to the pituitary macroadenoma, bilateral atrophy of the zona reticularis of the adrenal glands was observed histologically.

Treatment of an acromegalic cat with the dopamine agonist L-deprenyl.

Acromegaly was diagnosed in a 14-year-old domestic short hair cat presented for investigation and management of apparently insulin-resistant diabetes mellitus. Treatment with L-deprenyl and high doses of insulin was commenced. The L-deprenyl did not reduce the requirement for high doses of insulin and did not appear to reduce the clinical signs associated with the disease. The cat was euthanased one year after initial presentation.

Lactation associated with acidophilic pituitary adenoma, pheochromocytoma, and cystic endometrial hyperplasia in two goats.

Two unbred adult female goats were examined for persistent, inappropriate lactation. Prostaglandin F2 alpha treatment was ineffective in relieving the condition. Over 5 months, 1 goat developed evidence of CNS disease; this same goat had persistently high serum prolactin concentrations. At necropsy, both goats had an acidophilic adenoma of the pars distalis, a condition that, to our knowledge, has not previously been reported in goats. In addition, both goats had pheochromocytomas and cystic endometrial hyperplasia, conditions that are rarely reported in small ruminants. The inciting cause of inappropriate lactation in goats can be difficult to determine. Pituitary adenomas should be suspected when treatment with prostaglandins is unsuccessful, signs of CNS disease develop, or persistently high serum prolactin concentrations are detected.

Diabetes mellitus in a dog with a growth hormone-producing acidophilic adenoma of the adenohypophysis.

A 9-year-old male Doberman Pinscher was referred to the Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, for polyuria/polydipsia, anorexia, and vomiting. Laboratory examination of blood and urine revealed hyperglycemia, glucosuria, and acidosis. Diabetes mellitus was diagnosed but was very resistant to subsequent insulin treatment. At the owners' request, the dog was euthanatized and a postmortem examination was performed. In addition to hepatic, pancreatic, and renal changes compatible with diabetes mellitus, an acidophilic adenoma of the adenohypophysis was found. Immunohistochemical staining for growth hormone, adrenocorticotropic hormone, and prolactin showed a strong immunolabeling for growth hormone within the cytoplasm of the tumor cells. Although growth hormone level was not measured in the plasma, our findings suggest that the diabetes mellitus in this dog was caused by excess growth hormone secreted by the pituitary neoplasm.

Prolactin-secreting pituitary adenomas with mammary dysplasia in New Zealand white rabbits.

Nine aged (mean age = 3.2 years) nulliparous New Zealand white rabbit does were found to have markedly enlarged teats. The teats were frequently engorged with fluid but were not hot and did not cause signs of pain. The number of affected teats per animal ranged from 1 to 8 (mean = 4). The teats and associated glandular tissue were typically discolored grey, blue, or greenish black (n = 6). Prolactin concentrations were evaluated by radioimmunoassay. Serum prolactin concentrations ranged from 22.4 ng/ml to 2.21 micrograms/ml (mean = 397.3 ng/ml), which was 10- to 1000-fold greater than normal values in nonpregnant rabbits. Conventional radiography of the skull of six rabbits did not reveal pituitary enlargement. Necropsy revealed an enlarged pituitary gland and sella turcica in six of nine does. The diaphragma sellae had ruptured in two rabbits. All nine rabbits had pituitary acidophil adenomas. The neoplastic portions of the pituitaries were diffusely immunoreactive when stained immunohistochemically for prolactin. In contrast, only small clusters of five to seven cells stained positively in normal pituitaries selected as controls. Histologic examination of the mammary glands revealed numerous large dilated cystic spaces containing proteinaceous fluid. Many cysts had numerous papillary epithelial infoldings. The cystic dilations extended into and included the teat canal producing the gross appearance. Prolactin-secreting acidophil adenomas have not been previously reported in the rabbit, and the association with mammary dysplasia is unique.