'Spare' Luteinizing Hormone Receptors: Facts and Fiction

Livio Casarini; Daniele Santi; Manuela Simoni; Francesco Potì

doi:10.1016/j.tem.2018.01.007

'Spare' Luteinizing Hormone Receptors: Facts and Fiction

Trends Endocrinol Metab. 2018 Apr;29(4):208-217. doi: 10.1016/j.tem.2018.01.007. Epub 2018 Feb 9.

Authors

Livio Casarini¹, Daniele Santi², Manuela Simoni³, Francesco Potì⁴

Affiliations

¹ Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, NOCSAE, via P. Giardini 1355, 41126 Modena, Italy; Center for Genomic Research, University of Modena and Reggio Emilia, via G. Campi 287, 41125 Modena, Italy. Electronic address: livio.casarini@unimore.it.
² Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, NOCSAE, via P. Giardini 1355, 41126 Modena, Italy; Department of Medicine, Endocrinology, Metabolism and Geriatrics, Azienda Ospedaliero-Universitaria di Modena, NOCSAE, Via P. Giardini 1355, 41126 Modena, Italy.
³ Unit of Endocrinology, Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, NOCSAE, via P. Giardini 1355, 41126 Modena, Italy; Center for Genomic Research, University of Modena and Reggio Emilia, via G. Campi 287, 41125 Modena, Italy; Department of Medicine, Endocrinology, Metabolism and Geriatrics, Azienda Ospedaliero-Universitaria di Modena, NOCSAE, Via P. Giardini 1355, 41126 Modena, Italy.
⁴ Department of Medicine and Surgery - Unit of Neurosciences, University of Parma, via Volturno 39/F, 43125 Parma, Italy. Electronic address: francesco.poti@unipr.it.

PMID: 29429918
DOI: 10.1016/j.tem.2018.01.007

Abstract

It is common opinion that maximal activation of luteinizing hormone (LH)-dependent steroidogenic signal occurs at <1% of human LH/choriogonadotropin (hCG) receptor (LHCGR) occupancy. This effect would be a consequence of an excess of receptors expressed on the surface of theca cells, resulting in a pool of LHCGRs remaining unbound (spare). This concept was borrowed from historical pharmacological studies, when discrepancies between ligand-receptor binding and dose-response curves of cAMP were evaluated by treating mouse or rat Leydig cells with hCG in vitro. Recent findings demonstrated the specificity of LH- and hCG-dependent effects, receptor heterodimerization, and differing behaviors of rodent versus human gonadotropin-responsive cells, which may help to revise the 'spare' LHCGRs concept applied to human ovarian physiology and assisted reproduction.

Keywords: follicle-stimulating hormone; folliculogenesis; gonadotropin; luteinizing hormone; ovary; spare.

Publication types

Review

MeSH terms

Animals
Female
Granulosa Cells / metabolism*
Humans
Ovary / metabolism*
Receptors, LH / metabolism*

Substances

Receptors, LH