propylthiouracil and Starvation

Exposure of rats to higher environmental temperature (36-37 degrees C) decreased the capacity of their kidney mitochondria to oxidize succinate. The decrease was corrected on the addition of exogenous cytochrome c. Kidney mitochondria of heat-exposed animals showed decreased rates of H2O2 generation when alpha-glycerophosphate, but not succinate, was used as electron donor. These mitochondria also showed decreased activity of alpha-glycerophosphate dehydrogenase but not of succinate dehydrogenase. The content of cytochrome c in kidney mitochondria of heat-exposed animals was low even though the concentration of the pigment in the whole tissue did not decrease. Starvation as well as administration of an antithyroid agent like propylthiouracil simulated some of the effects of heat exposure on kidney mitochondria, but the cytochrome c-dependent reversal of inhibition of oxidation was obtained only in heat exposure.

Topics: Animals; Body Weight; Cytochromes; Glycerophosphates; Hot Temperature; Hydrogen Peroxide; Kidney; Male; Mitochondria; Organ Size; Oxidation-Reduction; Oxidative Phosphorylation; Propylthiouracil; Rats; Starvation; Succinates; Succinic Acid

The interaction of glucocorticoid (GC) and thyroxine (T4) in the generation of the hepatic enzyme overshoot and lipid response to starvation-refeeding was studied. Male Sprague-Dawley rats were either left intact, or treated with propylthiouracil (PTU), or adrenalectomized (ADX), or ADX and/or PTU treated and treated with GC and/or T4. One-half of each of these treatment groups was fed a 65% glucose diet while the remaining rats were starved for 48 hours and refed the glucose diet for 48 hours. After decapitation, hepatic lipid and glucose-6-phosphate dehydrogenase (G6PD) activity were determined. Rats treated with only PTU had less of an enzyme overshoot than nontreated rats, and the full overshoot response was restored with T4 treatment. ADX rats did not have the typical enzyme overshoot response to starvation-refeeding. However, ADX rats had their overshoot response restored with GC. PTU-treated ADX rats had more of an overshoot response than did ADX rats. When T4 was administered to PTU-treated ADX rats there was less of an enzyme overshoot; however, when both T4 and GC were administered to the PTU-treated ADX rats, the overshoot response was fully restored. The liver lipid response to starvation-refeeding followed a similar pattern except that in PTU-treated rats the liver lipid levels were significantly higher in the starved-refed rats than in the ad libitum-fed rats. These results indicate that T4 and GC play a role in the G6PD and liver lipid response to starvation-refeeding.

Topics: Adrenalectomy; Animals; Body Weight; Drug Interactions; Food; Glucosephosphate Dehydrogenase; Hydrocortisone; Lipid Metabolism; Liver; Male; Organ Size; Propylthiouracil; Rats; Rats, Inbred Strains; Starvation; Thyroxine

Topics: Animals; Diiodothyronines; Dithiothreitol; Edetic Acid; Hyperthyroidism; Hypothyroidism; Iodide Peroxidase; Kinetics; Liver; Male; NADP; Peroxidases; Propylthiouracil; Rats; Starvation; Thyroidectomy; Thyronines; Triiodothyronine; Triiodothyronine, Reverse

The effects of underfeeding and manipulation of the thyroid axis on ovarian function were determined in young and old rats. The depressant effect of reduced food intake on ovarian cycling in young females was potentiated by chemical thyroidectomy, while young anestrous, underfed rats cycled when their diet was supplemented with thyroid extract. These observations iindicate that cycling aberrations in underfed rats may occur secondarily to an altered thyroid state. To determine if thyroid state influences ovarian function in old animals, constant estrous (CE) rats were underfed or chemically thyroidectomized. All underfed rats eventually cycled, while the response to chemical thyroidectomy alone, though still effective, was less dramatic. Realimented CE animals eventually returned to a pattern of constant vaginal cornification. Underfeeding had no effect on ovarian function in old recurrently pseudopregnant females however, these rats responded to thyroid treatment with renewed cycling. 4-6 (YC) 10-12 (PEP) month old females entered a persistent vaginal estrous condition when fed low doses of thyroid extract with their ad libitum diet. When the thyroid supplemented diet was discontinued, YC females resumed regular cycling, whereas the vaginal smear in 40% of the PEP rats remained cornified. Cycling could be restored in YC-thyroid induced CE rats by electrochemical stimulation of the medial preoptic area. These date suggest that senile deviations from normal cycling in the aging reproductive system may be affected by alterations in the thyroid state.

Topics: Aging; Animals; Electric Stimulation; Estrus; Female; Ovary; Ovulation; Pregnancy; Propylthiouracil; Rats; Starvation; Thyroid Gland; Thyroid Hormones; Thyroidectomy

Topics: Animals; Birds; Diiodotyrosine; Female; Iodine; Iodine Radioisotopes; Male; Monoiodotyrosine; Propylthiouracil; Seasons; Starvation; Thyroid Function Tests; Thyroid Gland; Thyrotropin; Thyroxine

Topics: Adipose Tissue; Alanine Transaminase; Animals; Corticosterone; Liver; Liver Glycogen; Male; Metyrapone; Organ Size; Phenylalanine; Propylthiouracil; Proteins; Rats; Starvation; Tyrosine; Tyrosine Transaminase; Water

Topics: Acidosis; Adult; Coma; Cortisone; Diabetic Ketoacidosis; Glucose Tolerance Test; Humans; Hyperglycemia; Hyperthyroidism; Male; Propylthiouracil; Starvation

Topics: Animals; Cattle; Dactinomycin; Depression, Chemical; Drug Antagonism; Hypothyroidism; Male; Pituitary Gland; Propylthiouracil; Rats; RNA, Messenger; Starvation; Thyroid Gland; Thyrotropin; Thyroxine