Effect of parathyroid hormone and calcium ions on substrate oxidation by isolated glomeruli of the rat.
Effect of Ca2+ and parathyroid hormone (PTH) on 14 CO2 production from certain metabolic substrates by isolated glomeruli of rat kidney were examined. Increasing calcium concentration in the incubation medium inhibited 14CO2 production from 14C-labeled alpha-ketoglutarate and succinate, stimulated 14CO2 production from [1-14C]glucose and [1-14C]glutamate, but was without effect on that from [6-14C]glucose. PTH in the presence but not in the absence of Ca2+ inhibited 14CO2 production from labeled alpha-ketoglutarate and glutamate but not from labeled glucose. Additions of cyclic AMP as well as hormonal agents known to act directly on the glomureli, such as histamine, epinephrine, prostaglandin E2, vasopressin, angiotensin II and insulin, did not alter 14 CO2 production from labeled alpha-ketoglutarate. These data show the presence of calcium-dependent inhibitory actions on PTH on oxidation of alpha-ketoglutarate and glutamate which may be independent of cyclic AMP. These metabolic effects of PTH may underlie the alteration in the glomerular ultrafiltration coefficient and glomerular filtration induced by the hormone.
D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D002245:Carbon Dioxide / Q000378:metabolism; D000242:Cyclic AMP / Q000494:pharmacology; D005971:Glutamates / Q000378:metabolism; D018698:Glutamic Acid; D007656:Ketoglutaric Acids / Q000378:metabolism; D007678:Kidney Glomerulus / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D010084:Oxidation-Reduction; D010281:Parathyroid Hormone / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains
D005971:Glutamates; D007656:Ketoglutaric Acids; D010281:Parathyroid Hormone; D002245:Carbon Dioxide; D018698:Glutamic Acid; D000242:Cyclic AMP; D002118:Calcium