Circuit diagrams and model equations for the hormone regulatory motifs. Diagrams are generic, stimulation and inhibition may be exchanged. h = hormone concentration,m=metabolite concentration, G = endocrine gland mass, u = input signal, r = rate constant for hormone removal, q = hormone/metabolite specific production rate (maximal secretion rate per unit biomass of secreting cell type), s = hormone sensitivity, a = rate constant for metabolite removal, c = cell proliferation/growth rate, d = cell death or removal rate.
The five classes of endocrine circuits and their dynamic response to brief and prolonged input stimuli. Diagrams are generic, and stimulation and inhibition may be exchanged. a−e Class 1−5, respectively. Metabolite, hormone and gland mass dynamics from simulations with a brief input pulse of 9 days (dashed blue line) or a prolonged pulse of 150 days and a second prolonged pulse with twice the amplitude at day 350 (orange line). Constant tissue in class 2 indicates that the secreting cell type growth is not regulated by elements in the circuit. The functions of the circuits are summarised. Simulation parameters are q = q3 = 16/day, q1 = 288/day, q2 = 48/day, rClasses1–3 = r3 = 16/day, r1 = 288/day, rClass4 = r2 = 48/day, c = c1 = c2 = d = d1 = d2 = 1/15/day, s = 48/day, a = 16/day.
Transition between subclinical and clinical Cushing’s syndrome cases for pituitary and adrenal tumours. a: Schematic showing how an adrenal cortisol-secreting tumour causes the native (non-neoplastic) adrenal cortex cortisol-secreting mass to shrink. Clinical disease appears in cases in which the adrenal cortex cortisol-secreting mass shrinks to zero. b: CRH, c: ACTH and d: cortisol as a function of adrenal tumour cortisol secretion rate β. e: Schematic showing how a pituitary ACTH-secreting tumour causes the native pituitary corticotroph mass to shrink. Clinical disease appears in cases in which the pituitary ACTH-secreting mass shrinks to zero. f: CRH, g: ACTH and h: cortisol as a function of pituitary tumour ACTH secretion rate α. Simulations used q1 = r1 =288/day , q2 = r2 = 48/day , q3 = r3 = 16/day, bP = aP = bA = aA = 1 15/day , r = 1/day, Kgr = 4, n = 3, K = 1, u = 1, and ζ = 0.1.
#Endocrine feedback loops belong to the important foundations of life. However, consistent underlying rules are still lacking. Now, Moriya Raz, Uri Alon, and co-authors describe 5 classes of control circles.
www.livivo.de/doc/M41271754
pubmed.ncbi.nlm.nih.gov/41271754/
doi.org/10.1038/s414...